1. Resistivity and Resistance
Resistivity is a property of a material describing the degree to which the material opposes the flow of charges through the material.
Resistance is a property of a device describing the degree to which the device opposes the flow of charges through the device.

2. Resistivity
Resistivity depends on material properties that are mostly beyond the scope of this course.
Resistivity for a few common materials:
Material Resistivity, ρ (Ωm)
Silver x 10-8
Copper x 10-8
Gold x 10-8
Aluminum x 10-8
Silicon x 102
De-Ionized Water x 105
Diamond x 1012

3. Resistivity
Resistivity depends on temperature. The temperature dependence is particularly important for conductors.
Material Resistivity, ρ (Ωm) α (K-1)
Silver x
Copper x
Gold x
Aluminum x
Silicon x 102
De-Ionized Water x 105
Diamond x 1012

4. Resistance
Resistance depends on the material (resistivity) and the geometry of the device.
Resistance is proportional to device length and
inversely proportional to cross-sectional area.

5. Resistance
Resistance depends on the material (resistivity) and the geometry of the device.
(If the cross-section is not uniform throughout the length of the device, one must integrate to determine R.) y x z

6. Resistance
Consider connecting two resistors of the same cross-sectional area in series.

7. Resistance
Consider connecting two resistors of the same length in parallel.

8. Circuits
Quantity
Series
Parallel
Capacitance
Resistance
Potential Difference
Current
Charge on Capacitor

9. Circuits
Quantity
Series
Parallel
Capacitance
Resistance
Potential Difference
Current
Charge on Capacitor
OSE’s